Using aerodynamic vortex generators on cars 

Julian, what the air tabs do effectively do is improve the handling characteristics of boxy vehicles travel trailers etc. an example; I had a Chevrolet Astro van which is quite boxy and it had quite a bit of play in the steering box and it would not drive straight it would yaw back and forth going down the road and I’d have to saw back and forth on the wheel to keep it tracking straight which was not very relaxing. I plastered the sides and back of the van with air tabs at the very back where the airflow was leaving the van and the van tracked as straight as an arrow! I could drive with one hand! As you say I didn’t see any quantifiable improvement (or detriment) to fuel mileage BUT I would totally use them on a travel trailer and on a tow vehicle at the figment gap to reduce drag between the two bodies. I’d also consider placing them on a deflector wing on my tow vehicle to try to bridge that gap. What they also did very well was to markedly reduce the “push” and “suck” effect when passing/being overtaken by a large semi truck. I wonder if somehow the voticies create a type of virtual tail cone on a square backed vehicle? All I know is they help markedly in this regard and I’d use them for that again.

The guys at Myth Busters did a similar testing awhile back. Their contraption actually lessen the air turbulence at the rear of the roof line on the car used in the test.

Another great lesson. Thank you so much.

Very informative! I've installed VGs on multiple vehicles. I've found that obtaining the optimal position(s) on each car is 'half of the battle'. I usually road test w/colored chalk line powder to find the separation areas. My present 'rolling experiment' is a `07 Honda Accord w/"Gas Pods". I see complete downward airflow on all areas of the rear window where it didn't exist prior.

I totally believe in the value of VGs'. My buddy put them on his E55 Baron (light twin engine prop) and they dropped his stall about 10 knots and dramatically helped handling at lower speeds. As to an auto, I believe that placement is crucial and that putting them on the trailing edge of the roof may not be the optimum location (look at the Honda Legend placement 1/3 down from the rear roof line which makes more sense to me). Most are placing them for aesthetics like the WRX-Sti and the Evos . Until some objective testing is done in an aerodynamic chamber or other facility, I will reserve judgment on their efficacy since although we know they work, we just are NOT sure where they need to be placed to work. Great job on the presentation @Julian Edgar.

Vortex generators utilize the same effect that dimples on a golf-ball utilize, except on a golf ball we have to cover the entire ball because we don't know where the front and back are because the ball is spinning, whereas on a car or airplane we know where the front and back are so we can only place them strategically.

At the ~6 minute mark, where you're discussing the "filling the wake" possibilities, I believe that is specifically for bluff-ended vehicles [ie: the ones whereupon you mostly see the Airtabs implemented] like semi-trailers and motorhomes. The recommended use of Airtab approximately 1 ft in front of the trailing edge of the vehicle, iirc. The irony of imparting better airflow attachment by selective detachment of some fraction thereof is not lost on me...

You should check out the aerodynamics of F1 racing very interesting how they dedicate most of the car to airflow and use vortex generators to create the y250 vortex and improve the cars performance

Toyoda has a video showing their VG as installed on their autos.

Do you think putting these on top of the cab of a pickup truck with a tonneau cover to pull the air behind the cab to attach on the bed cover sooner?

these work if you use them correctly, but no one uses them correctly. in fact the way most people use them they actually make the car less efficient in terms of drag.

I can see that promoting better flow attachment would be helpful in stabilizing and directing air to a wing or spoiler. On a that test Prius what benefit would there be? As stated, there is no wake-fill and thus no drag reduction and no improvement in fuel economy.

lol, need to include an air ionization/plasmafication stage, then use magnetohydrodynamics to create the vortex

Hi Julian, do you think these would work effectively when placed in front of a wheel well? I know many manufacturers are using air curtains / redirected air to reduce wheel well drag.

Semi trucks use these to increase fuel mileage.

Julian, in the states they use something called " trailer tails ". on semi trailers. Why do these work??

The VG's on the evo are mounted to a rounded plate with a larger radius than the roof, helping attachment. The rounded plate itself could even wick the boundary layer down, considering it has a smooth leading edge. I have a side question for you? Are VG's bad for attachment along a flat underbody, I was thinking they could help with attachment but may create turbulence. Possibly placing them 1-2 feet from the end to promote suction?

Is there a spray-able " micro- vortex generator"?? Plasti dip with electrostatic particles that can be manipulated to self arrange or with a charge . Would a " VG" evan be efficient on a vary small scale?? Just a thought

They should be used in the car like in the intake manifold.

what about the other designs, I can't see anything supporting design principles via sellers.

I have a Mazda Miata and being a convertible the interior is quite turbulent. I was thinking about building a strip of vortex generators aft of the trailing edge of the windshield. In your opinion would the reduce turbulent air hooking around the top of the windshield or would it be ineffective because there is no boundary layer past the top of the windshield? Thank you

Sir, In the US these VGs are used on large box shaped vehicles at the trailing edge. Is there and benefit that could be achieved on the front of a box shaped vehicle like a Jeep Wrangler? Could a VG help with the transition between the front bumper, grill, hood and fender flares or would this cause more drag? Thanks John

EcoFins have a much better adhesive and less expensive.

Back of my carado i339 Motorhome is a flat slab .. I wonder if and where I should fit them..

I have a Tesla Y. Where should the VGs be?

Do these stop dirt hitting the rear windscreen on a Isuzu MUX?

How about on the trailing edge of the roof on a pickup truck which has a 90 degree window behind it and a tonneau cover of the back..?

I have a Lance 1575 travel trailer which has a box shaped rear. Do you think adding these vortex generators to the rear sides and top of the trailer could reduce negative pressure, and how could I go about testing the effectiveness / placement (without a wind tunnel).

What about on the roof of my dual cab amarok to help the air flow over the bed with a cover on it?

Would these change anything on a van or SUV with a square back?

We just ran AirTabs on and E36 BMW in the wind tunnel. We did only do one run in one location (wind tunnel time is expensive!) but they were terrible. Added a few pounds of drag and less then one pound of downforce (or loss of lift). They are in this video here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KI1gi9_6WRM.html

What brand?